Fluid controlled feathering means for propellers



Dec. 14, 1948. H. D. HURT 0 FLUID CONTROLLED FEATHERING MEANS FOR PROPELLERS Filed July 10, 1946 Patented Dec. 14, 1948 FLUID CONTROLLED FEATHERING MEANS FOR PROPELLERS Hansford D. Hurt, Pasadena, Calif. Application July 10, 1946, Serial No. 682,480

9 Claims.

This invention relates to a fluid controlled feathering means for propellers.

Among the objects of the invention are: to simplify the construction of devices of the class to which the inyention pertains by reducing the number of work ng parts; to reduce the amount of friction heretofore produced in changing the pitch of the propeller blades; and to provide a superior means for positively holding the propeller blades at the adjusted pitch.

A more specific object is to provide improved means to conduct an operating fluid, under the required pressure, to and from the parts to be operated thereby.

Other objects, advantages, and features of invention will hereinafter appear.

Referring to the accompanying draw ng, which illustrates a preferred embodiment of the invention,

Fig. 1 is a partly sectional and partly elevational View of a propeller unit showing the hydraulic mechanism for automatically feathering the propeller blades.

I Fig. 2 is a sectional view taken on line 2-2 of Fig. 1.

Fig. 3 resembles Fig. l in that it is also a partial plan and partial section, but is of a more diagrammatic nature. This view illustrates the principle of the invention as applied to a twin propeller as, for example, in a helicopter.

Fig. 4 is an enlarged reproduction of the encircled part of Fig. 3, illustrating the means for gonducting the hydraulic feathering control uid.

Referring in detail to the drawing, the principle of controlling the feathering blades is most clearly shown inthe right hand portion of Fig. 1, where there is shown a T'-me'mber 1 consisting of a central tubular stem 8 from which branch the twin tubular arms 9, said stem having a tubular end portion l onto which is screwed a pointed streamlined closure cap 11.

Each of the arms 9 has a sufliciently thick wall to accommodate an inner duct 12 and outer duct 13 through which the hydraulic pressure fluid flows. Said duct 12 opens at 12a into the inner end portion of a cylindrical chamber 14 in the arm 9, and duct 13 opens at 13ainto the outer portion of said chamber 14. Hydraulic fluid pressure entering at l2a moves outwardly the piston head I 5, into which is screwed the rod section 16 that has a fluidtight workingfit in a cross wall 11 at the outer end of the chamber 14.

As the fluid introduced at 12a moves the rod section 16 outwardly it also moves outwardly a sleeve 18 carried (preferably integrally) by said rod section. Said sleeve carries externally a helical male thread l9 which has a working fit within a corresponding female thread 20 formed internally of the diametrically reduced outer end portion 21 of the tubular arm 9. Said sleeve 18 carries a plurality (four being shown) of spline ribs 22 which cooperate with an equal number of spline grooves 23. Said grooves 23 are formed on the exterior of a shankportion 24 of the propeller blade. Said shank 24 has around it an integral rib or flange 25. The adjacent end portion of the tubular section 2| is diametrically enlarged at 21a thus providing an internal annular shoulder 26 against which abuts one side of said flange 25, and a split collar 21 is provided which abuts the o posite side of said flan e, the flange being confined between these two parts with a rotational working fit, so that the shaft 24 can rotate but cannot move longitudinally in relation to the adjacent parts as the sleeve 18 is activated by the piston to turn and move longitudinally.

The split collar 21 is of a stepped character, thus providing it with an annular end portion 21a which screws into the enlarged end portion 21a of the tubular section 2 l.

The outward movement of sleeve 18 has been described and is reversed by hydraulic fluid being injected into the cylinder 14 through the, duct opening 13a, thus applying fluid pressure'on the outer face of the head 15 and forcing the fluid out on the opposite side through the opening 12a. Escape of the fluid from the cylinder is prevented by fluid seal 28 held in place by an externally screw threaded plug 29 abutting, against the shoulder 30. The seal 28 and plug 29 can be introduced through the open end of the tubular end portion 10 before the cap 11 is applied thereto. v

Fig. 3 shows the device applied to a pair of reversely rotatable propellers and 36 such, for example, as are used on airplanes or helicopters. The pair of propellers 35 are carried by a central tubular shaft 31 having a diametrically reduced lower end portion 38 to which is secured av bevel gear 39 meshing with a driving bevel gear 40 on driving shaft 41 of motor 42, said gears being enclosed in a suitable casing 43.

The lower part of the shaft section 31 carries a bevel transmission gear 44 meshing with the bevel idler gears 45 which, in turn, mesh with a bevel gear 46 carried by the lower part of the exterior tubular shaft 41, the upper part ofwhich carries the aforesaid propeller blades 36.

A stationary gear casing surrounds the four bevel gears which have just been mentioned, said casing composing a lower cap member 48 and an upper cap member 49. These cap members respectively have internally screwthreaded peripheral flanges 48a and 49a which screw onto an intermediate annular gear case member 58 formed in a mounting plate l. The aforesaid idler ears 45 are shown rotatably mounted upon' bearing screws 52 screwed intosuitable bores provided for them, said bores passing through diametrically opposite sides of the intermediate gear case member 50 and terminating in the adjacent parts of the mounting plate 5|. Said mounting plate'Sl may be bolted to a suitable support 53 .a fragmentv of which is shown.

The pressure fluid conducting system has already been in part described in tracing out the terminal portions of the ducts l2 and I3 shown" in Fig.1. In Fig. 3 the ducts I23: and i311: illustrate portions of a more extensive pressure fluid conducting system constructed according to the same principle. Said ducts lZm and I3zc pass downwardly through the shaft section 31 and respectively open into circular grooves 60 and Bi produced by and between a series of annular concentric ribs 62 projecting from the lower face of the aforesaid gear. The lower gear case member 48 is furnished with concentric grooves 63 (see Fig. 4) Within the upper portions of which said ribs 62 have working fits, the taper of said ribs and grooves being designed to take up wear. Suitable packing 64 may be provided.

I The grooves 60 and 6!, and their surrounding structure, constitute glands by which a substantially tight Working oonection with the channels for the transmission of pressure fluid therethrough as the shafts revolve is provided. The gland construction as shown is subject to modification.

With the groove 60 communicates the duct '65 which leads through the gear casing section 48 to the pipe 66 and with the groove 6i communicates a corresponding duct 66 that com municates with'a pipe 68. It is to be understood that said pipes 6! and 68 lead to any desired conventional distributingvalve structure to control ingress and egress of the hydraulic pressure fluid.

The groove and duct structure of Fig. 4 is typical of the corresponding structure between the uper gear 46 of Fig. 3 and the case member -49 hence is identified by lettering as 56m and 68a: of Fig. 3, the pipe 681: communicating with a duct 69 in the outer tubular shaft M which corresponds with the aforesaid duct [2 (or 12:13) I and pipe 683: communicating with a duct H! that corresponds with the aforesaid duct l3 (or l3w).

It will be observed that the two idle gears 45 of Fig. 3 cause the upper gear to rotate in the reverse direction tothe lower gear 44 which is necessary in case the propeller blades 35 and 36 form a part of a helicopter.

I claim:

1. In a structure of the kind described, a

T-member the arms of which are tubular, there being a closed-in piston chamber in the inner end portion of each of said arms. a sleeve carried within each of said arms and having an axial "stem which carries a head having a Working fit in the adiacent piston chamber, means for sealingoif the end port ons of each of sa d piston "chambers from the adioining parts of the arm in which they are located, one of said sealing means for each piston chamber consist g of a turning movements to said sleeves, and a plurality of propeller blades, one carried axially by each of said sleeves, each of said propeller blades having a cylindrical shank which is fastened in a tur-nablenonslidable manner in the outer end portion of the sleeve at its side of the T-member.

2. The subject matter of claim 1, and said spline and groove relation consisting of a spline carried by said sleeve'and a'groove in. the tubular part therearound;

3. The subject matter of claim 1, and said blade shank and sleeve having an interfitting spline and groove relation to each other.

4. In a structure for mounting and reversely rotating two pairs of propeller blades about a common axis, an inner propeller shaft carrying propeller blades atone end, driving means operatively connected with the opposite end of said shaft, a bevel gear concentrically carried by said shaft, an outer tubular shaft surrounding said inner shaft, propeller blades mounted on one end of said outer shaft, a bevel gear concentrically carried by the opposite end of said outer shaft, a casing for said gears, idler bevel' ears mounted in said casing andpositioned to-cause the rotationin'one direction of the first recited gear to drive the gear of the outer shaft in the opposite direction, there being an interfitting groove and'rib'relationship between inner surface portions of said casing and adjacent face portions of said reversely rotatable gears thus forming circular closed-in fiuidconducting channels between said casing and the last recited gears, said channels being concentric to the aXis of rotation of said inner and outer shafts, ducts leading through said wall of said casing to conduct fluid under pressure to said. channels, feathering means for the aforesaid'propeller blades located between said blades and the shafts carrying them and operable by fluid pressure, and ducts leading through said inner and outer shafts to conduct pressurized operating fluid fromsaid channels to and from said feathering means.

5. Fluid controlled feathering means for propeller blades, comprising a'T-member the arms of which are tubular and form a closed-in piston chamber in the inner end portion thereof and a companion sleeve holding'chamber in the outer end portion of each of said arms, a piston reciprocable and freely rotatable in said piston chamber, fluid actuating ducts connected with the opposite end portion of the piston chamber and on opposite sides of the piston therein, a sleeve in said companion sleeve holding chamber having helical threaded connect on with the inner wall thereof, and a propeller blade swiveled in the outer end portion of said companion sleeve holding chamber, said propeller blade having an inner extension splinedlon'gitudinally to said sleeve, whereby the reciprocable movement of said piston is converted into therotary adjustment of said propeller blade.

6. In a structure as Idefi'ned'in claim 5', the propeller blade being swiveled by an annular bearing seat in the outer end portion of the companion sleeve holding chamber, a shaft extended on the inner end portion of said blade having an integral annular shoulder journaled against said bearing seat, a collar enveloping said shaft and screw threadedly engaged in the outer end portion of said sleeve rotatively against said annular shoulder.

'7. Pressure fluid controlled feathering means for propeller blades, comprising a support having laterally extending tubular arms, each of said arms forming a piston chamber in the inner portion thereof and a companion sleeve holding chamber in the outer end portion thereof, a piston freely movable in said piston chamber, fluid actuating ducts connected with the opposite end portions of the piston chamber on opposite sides of the piston therein, a sleeve connected with the wall of said sleeve holding chamber whereby revolving motion is imparted to said sleeve by the reciprocation of said piston, a propeller blade having a supporting shaft journaled in the outer end portion of the wall structure of said sleeve holding chamber and splined longitudinally to said sleeve whereby the reciprocable motion of the fluid propelled piston is converted into the rotary movement of the companion propeller blade to cause feathering of the blade.

8. In a structure having reversely rotatable propeller blades, 2. pair of propeller blade supporting shafts rotative about a common axis, driving means for revolving said shafts in opposite directions, and fluid actuating feathering means between the propeller blades and said shafts, fluid conducting channels extended through said shafts and connected with said feathering means to actuate the latter, a casing in which portions of said shafts are revoluble, and closed in glands in said casing connected with said channels in said shafts by which actuating fluid is conducted to said channels as the shafts are revolved.

9. In a structure having a pair of propeller blade supporting shafts rotative about a common axis, driving means for revolving said shafts independently, feathering means between each of the propeller blades and a companion one of said shafts, fluid conducing channels extended through said shafts and connected with each of said feathering means to actuate the latter, a casing in which portions of said shafts are revoluble, and closed in glands in said casing connected with said channels in said shafts by which actuating fluid is conducted to said channels as the shafts are revolved.

HANSFORD D. HURT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

